Nitrous oxide emission from soil of the Mata Atlantica, Rio de Janeiro State, Brazil

Emissions of nitrous oxide by the soils of the Mata Atlantica subtropical forest were measured, on 21 days spread over one year, using a static chamber technique with natural flux calculation from nonlinear curves of chamber concentration versus time. The average of measured fluxes was 4.8 ng N cm(-2)h(-1) (n=131). Emission rates increased by an order of magnitude during and after rainfall, and a mean flux from this environment, weighted for mean weather conditions, was estimated as 3.6 ng N cm(-2)h(-1). These fluxes are comparable to others reported for humid tropical forests, among the highest for any environment.